The present disclosure relates to a motor control system and a method for detecting an abnormality in a resolver/digital converter. In particular, the present disclosure relates to a motor control system that detects an abnormality in a resolver/digital converter that converts an analog angle signal output from a resolver that detects a rotation angle of a motor into a digital angle signal, and a method for detecting an abnormality in a resolver/digital converter.
Japanese Unexamined Patent Application Publication No. 2014-119284 (hereinafter referred to as Patent Literature 1) discloses a technique in which a redundant system is formed by providing two resolvers so that an abnormality in the resolvers can be detected. Specifically, an abnormality in at least one of the resolvers is detected by comparing signals output from these resolvers with each other. It should be noted that Patent Literature 1 fails to mention detection of an abnormality in a resolver/digital converter (hereinafter referred to as an R/D converter).
Japanese Unexamined Patent Application Publication No. 2005-345189 (hereinafter referred to as Patent Literature 2) discloses a technique in which an abnormality in an R/D converter is diagnosed (i.e., detected) by itself by using a simulation signal simulating an analog angle signal output from a resolver. Specifically, an abnormality in the R/D converter is detected by comparing the simulation signal input to the R/D converter with a digital signal output from the R/D converter.
Japanese Unexamined Patent Application Publication No. 2006-349561 (hereinafter referred to as Patent Literature 3) discloses a technique in which an abnormality in a resolver is detected by sampling an analog angle signal (a sine signal or a cosine signal) output from the resolver in a cycle of ½n (n≥2). Specifically, the resolver is determined to be abnormal when an integrated value of analog angle signals sampled in the above-described cycle is not within a threshold range. It should be noted that Patent Literature 3 fails to mention detection of an abnormality in an R/D converter.